E-mail Harvester Assignment

Objectives:

• Be able to define functions with parameters
• Be able to call functions with parameters
• Be able to use while loops
• Be able to traverse a string
• Be able to manipulate strings

References:

• Media:Strings_Python.pptx
• Strings
• Functions
• Conditionals (if-statements)
• Iteration (while loops)

Directions:

1. Write a function named findAtSymbol(s) that takes a single parameter, s, which is a string.
   • The function should traverse the string with a loop and use an if statement check if any character s[x] matches the "@" symbol. Your function should then return the index of the "@" symbol
   • Return -1 if no "@" symbol is found
2. Write a more generalized find() function named find(s, ch, index)
   • This time, the function should walk through s with a loop and look to see if any s[x] matches ch
   • The loop counter should start the search at index
   • return the location of the character ch in string s when there is a match
   • Return -1 if ch is not found
3. Create another find() function that does the same thing as the above find function, but instead of searching forwards, it searches backwards.
   • Name the function findBackwards(s, ch, index)
   • findBackwards() should also return an index
   • Return -1 if ch is not found
4. Create a new function named harvestEmail(s) where the user's sentence is passed in as s. Inside harvestEmail(s), use the functions that you defined above to isolate the e-mail address
   1. First, find the @-symbol using findAtSymbol() and storing the result in a variable.
   2. Find the space before the @-symbol using findBackwards() with the index of the AT-symbol. Store its result in a variable.
      • You will need to send the " " space character and index of the AT-symbol into your findBackwards() function call.
      • Example: findBackwards(s, " ", atSymbolIndex)
   3. Lastly, find the space after the @-symbol by using the find() function and storing the result in a variable.
      • You will need to send the " " space character and index of the AT-symbol into your find() function call.
      • Example: find(s, " ", atSymbolIndex)
   4. You should then return the slice of the string that contains the e-mail address .

Challenges:

• After you have tested harvestE-mail(s), create a new function named:
  • harvestAllEmails(lines) which prints out all the e-mail addresses from a given paragraph
• The e-mail harvester requires an e-mail to be separated by spaces. Modify your program so that it can detect an e-mail separated by non e-mail characters
  • Assume e-mail addresses are limited to using characters: A-Z, a-Z, 0-9, ., _, @

Testing:

# You should test harvestEmail() with the following doctest

def harvestEmail(s):
    """
      >>> harvestEmail("here is an email@address.com to test")
      'email@address.com'
      >>> harvestEmail("test this@this.com out")
      'this@this.com'
      >>> harvestEmail("is your e-mail a@a.com even in this sentence?")
      'a@a.com'
    """
 
if __name__ == '__main__':
    import doctest
    doctest.testmod()

Rubric

Criteria	Pts
'find' works perfectly	2
'findAtSymbol' works perfectly	2
'findBackwards' works perfectly	2
'harvestEmail' return correct string	2
Handles emails at the start or end of the string (e.g. no spaces before or after).	2
Bonus: Good variable names	+2
Bonus: Simple, clear code	+2
Maximum points	10 + 4